After the particle was found, the physicists discovered that their database, which helps thousands of scientists share data, was the stuff of a great startup. They were accepted in the Y Combinator program and launched Cloudant in 2008. The trio raised $16 million in venture funds along the way, hiring about 60 people and signing over 2,500 customers, including some huge ones like Samsung, Adobe and Nokia.

But here's the curious part: One of the investors in Cloudant's biggest and most recent $12 million round last May was Rackspace. That's one of IBM's biggest cloud computing competitors. It's curious that Rackspace didn't buy Cloudant for itself.

On top of that, Cloudant uses a database technology that competes with the one that IBM is trying to get people to use.

Specifically, Cloudant's main product is something called a database-as-a-service, meaning that companies can rent the database hosted on a cloud provider like Amazon, Rackspace or IBM's SoftLayer, paying for it on a monthly bases.

It's a type of database called noSQL, which is a popular tech for Internet apps and mobile apps.

So, with one fell swoop, IBM is no on both sides of the fight: It has backed MongoDB and it now owns a popular startup backed by a rival company that uses a rival technology. That gives lets it benefit from customers who use both cloud computing services.

Plus, IBM is moving in during a sensitive time for Rackspace, which is searching for a new CEO. Former CEO Lanham Napier retired unexpectedly earlier this month after posting a quarter that showed Rackspace was struggling to grow its all-important cloud computing business.

Disclosure: Business Insider founder Kevin Ryan is also co-founder of MongoDB.